Neuroprotective effect of Tiliacora triandra (Colebr.) Diels leaf extract on scopolamine-induced memory impairment in rats

Alzheimer's disease is characterized by progressive memory loss caused from alterations in the central cholinergic system. While existing medications often have adverse effects, traditional use of Tiliacora triandra in Thailand shows its potential as a revitalizing neurotonic agent. This study explores the impact of T. triandra leaf extract on cognitive behaviors, neuronal density, and oxidative stress in male rats with scopolamine-induced cognitive impairment. Experimental groups composed of a control, vehicle, positive control meditation, and T. triandra extract-treated groups (100, 200, and 400 mg/kg BW) over 14 days, with scopolamine administration (i.p.) between days 8 and 14. Results showed significant enhancements in the discrimination ratio and spontaneous alteration behavior percentage during novel object recognition (NORT) and Y-maze tests for scopolamine-administered rats treated with T. triandra extract or donepezil. In contrast, open field test (OFT)-assessed spontaneous locomotor activity displayed no significant difference. Notably, acetylcholinesterase (AChE) activity and malondialdehyde (MDA) levels reduced significantly in scopolamine-treated rats with T. triandra extract or the positive control. Moreover, neuronal density in the hippocampal CA3 region, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities increased significantly. However, catalase (CAT) activity exhibited no significant difference. In conclusion, T. triandra leaf extract shows promise in mitigating scopolamine-induced memory deficits, potentially attributed to increased neuronal density, inhibited AChE activity, reduced MDA levels, and enhanced antioxidant activities. This extract has potential as a therapeutic agent for Alzheimer's disease-associated memory impairment.